Patent GB-992783-A (GB)
Title: Improvements relating to shoe moulding apparatus
IPC: A43D3/02
Filed: 1963-11-22
Abstract: 992,783. Moulding shoe soles. AMERICAN RESEARCH & DEVELOPMENT CO. Nov. 22, 1963 [Jan. 18, 1963], No. 46282/63. Heading B5A. Shoe moulding apparatus for moulding a synthetic resin composition to a fabric upper comprises an open top sole mould, a last adapted to fit the top of the sole mould, dispenser means arranged to place a measured amount of a liquid composition in the sole mould and heating means associated with the sole mould and last for curing the resin composition. The moulding apparatus comprises a mould assembly 70 set in the top plate 12 of the cabinet assembly, a last assembly 80 pivotally supported on the cabinet assembly, and a dispenser assembly 40 and reservoir assembly 60 mounted on a plate 21 for reciprocal movement over the open mould cavities 75. The dispenser assembly 40 comprises a dispenser pump head 41 having a dispenser nozzle 42 for each mould cavity. The interior of the pump head communicates directly with the forward open ends of the cylinders 45, situated immediately behind the pump head and having pistons 46 and piston rods 47. The piston rods 47 are connected via stop blocks 54 to a cross rod which is connected to the rod of a fluid power cylinder 57 (Fig. 1, not shown) located between the cylinders 45 to provide reciprocal movement of the piston 46. Forward movement of the piston 46 is limited by stop member 52. As the piston 46 is withdrawn, check valve 44 is opened by suction effects and plastics material is drawn into the cavity in the pump head from reservoir 62. The plate 21 is mounted via strut member 22 on a bearing block 23 which is reciprocally mounted on slide bar 17. A plate member 24 integral with carrier block 23 is connected to the piston rod 38 of fluid cylinder 31 and its forward movement is limited by the adjustable stop member 28. The mould cavity 75 is provided with fluid passages 76 to which cooling fluid may be applied and a cylindrical electrical heater 79. The last assembly 80 consists of an upper solid form 82 and a heater containing member 84. A coolant passage 87 is provided between the lower surface of member 84 and the bottom plate member 85. Each of the last assemblies is bolted to an arm member 92 which is connected to a support 94 pivotally mounted on a trunnion 18. The last assembly is raised and lowered by means of power cylinder 101. A sequential timer controls operation of the machine. A cycle of operation begins with the dispenser assembly in the forward position (Fig. 2), the lasts having uppers mounted thereon and the mould cavities having plastic composition therein. Cylinders 31 are actuated to withdraw the dispenser assembly, the cylinder 57 at the same time being actuated to withdraw piston 46 and draw plastics material from reservoir 62 into cavities in pump 41. The power cylinders 101 are then actuated to lower the lasts into contact with the moulds. The heat input is adjusted to raise the mould temperature, and after a suitable interval the mould heater circuits are de-energized, and coolant circulated in cavities 76 and 87. The power cylinders 101 are actuated to raise the lasts. Cylinders 31 are then actuated to move the dispenser assembly to the forward position, then cylinder 57 is actuated to move pistons 46 forward to dispense the plastisol composition. The finished shoes are removed from the lasts, fresh uppers mounted thereon, and the machine is ready for another cycle. The temperatures are carefully controlled, the initial temperature of the mould being sufficient, at 210‹- 220‹ F., to expand the plastisol on the bottom and edge of the sole but leave the core and top surface fluid and non-expanded. The last temperature is at 240‹-260‹ F. in the gel range. After the last has descended to full closure with the mould, the temperature is raised to 350‹ F. above the gel range temperature of the plastisol. The coolant stabilizes the temperature of the last and mould at 160‹-220‹ F. Suitable compositions include polyvinyl chloride, rubber latex, epoxy resins, polyurethane resins and isocyanates.